create-parser.ts

import { NonterminalKind } from '@nomicfoundation/slang/cst';
import { Parser } from '@nomicfoundation/slang/parser';
import { LanguageFacts } from '@nomicfoundation/slang/utils';
import { maxSatisfying } from 'semver';

import type { ParseOutput } from '@nomicfoundation/slang/parser';
import type { ParserOptions } from 'prettier';
import type { PrintableNode } from '../slang-nodes/types.d.ts';

const supportedVersions = LanguageFacts.allVersions();
const supportedLength = supportedVersions.length;
const latestSupportedVersion = LanguageFacts.latestVersion();

function parserAndOutput(
  text: string,
  version: string,
  reason: string
): { parser: Parser; parseOutput: ParseOutput } {
  const parser = Parser.create(version);
  const parseOutput = parser.parseNonterminal(NonterminalKind.SourceUnit, text);

  if (!parseOutput.isValid())
    throw new Error(
      `We encountered the following syntax error:\n\n\t${parseOutput.errors()[0].message}\n\n${reason}`
    );

  return { parser, parseOutput };
}

export function createParser(
  text: string,
  options: ParserOptions<PrintableNode>
): { parser: Parser; parseOutput: ParseOutput } {
  const compiler = maxSatisfying(supportedVersions, options.compiler);
  if (compiler) {
    return parserAndOutput(
      text,
      compiler,
      `Based on the compiler option provided, we inferred your code to be using Solidity version ${compiler}. If you would like to change that, specify a different version in your \`.prettierrc\` file.`
    );
  }

  const inferredRanges: string[] = LanguageFacts.inferLanguageVersions(text);
  const inferredLength = inferredRanges.length;

  if (inferredLength === 0 || inferredLength === supportedLength) {
    return parserAndOutput(
      text,
      latestSupportedVersion,
      `We couldn't infer a Solidity version based on the pragma statements in your code so we defaulted to ${latestSupportedVersion}. You might be attempting to use a syntax not yet supported by Slang or you might want to specify a version in your \`.prettierrc\` file.`
    );
  }

  const inferredVersion = inferredRanges[inferredLength - 1];
  return parserAndOutput(
    text,
    inferredVersion,
    `Based on the pragma statements, we inferred your code to be using Solidity version ${inferredVersion}. If you would like to change that, update the pragmas in your source file, or specify a version in your \`.prettierrc\` file.`
  );
}